Camrelizumab and apatinib plus induction chemotherapy and concurrent chemoradiotherapy in stage N3 nasopharyngeal carcinoma: a phase 2 clinical trial

The antiangiogenic agent apatinib has been shown to clinically improve responses to immune checkpoint inhibitors in several cancer types. Patients with N3 nasopharyngeal carcinoma have a high risk of distant metastasis, however, if the addition of immunotherapy to standard treatment could improve efficacy is unclear. In this phase II clinical trial (ChiCTR2000032317), 49 patients with stage TanyN3M0 nasopharyngeal carcinoma were enrolled and received the combination of three cycles of induction chemotherapy, camrelizumab and apatinib followed by chemoradiotherapy. Here we report on the primary outcome of distant metastasis-free survival and secondary end points of objective response rate, failure-free survival, locoregional recurrence-free survival, overall survival and toxicity profile. After induction therapy, all patients had objective response, including 13 patients (26.5%) with complete response. After a median follow-up of 28.7 months, the primary endpoint of 1-year distant metastasis-free survival was met for the cohort (1-year DMFS rate: 98%). Grade≥3 toxicity appeared in 32 (65.3%) patients, with the most common being mucositis (14[28.6%]) and nausea/vomiting (9[18.4%]). In this work, camrelizumab and apatinib in combination with induction chemotherapy show promising distant metastasis control with acceptable safety profile in patients with stage TanyN3M0 nasopharyngeal carcinoma.

combination.With such an intensive regimen, one might have expected a higher CR rate.To interpret the data better, more information ought to be included in Table 1.For example, were the nodes bulky?How many levels were involved?What was the median gross tumour volume for the primary and nodal lesions?See my Comment #4a on stage classification.c.Perhaps, it would have been very useful to have EBV DNA response data to the induction phase.What was the proportion of patients who had a complete clearance by the end of induction treatment?What was the magnitude of drop in EBV DNA counts?d.Overall, this reviewer is unconvinced that the pathological responses are indicative of efficacy to this quintet combo.Moreover, conventional imaging, unless PET-CT, is not ideal for assessing CR of nodes; as a case in point, a lymph node of 3 cm size shrinking to 0.8 cm would be considered as PR?However, it could well be a pathological CR, since involved lymph nodes don't typically shrink entirely even months post-treatment (Li WF, et al. Oral Oncology, 2017).
If anything, EBV DNA and PET post-induction would have been highly informative of efficacy, especially since the concern with patients with N3 NPC is the risk of distant metastasesthus, the current measures do not offer insights in this regard.e. Perhaps, the authors could include some pre-and post-induction images of extreme responders to the induction treatment, which would be informative to the readers.7. Results -Figure 2: While the data compared with the historical cohort looks promising, such an analysis is flawed.Was the historical cohort matched in some way?Otherwise, this reviewer will urge the investigators to remove the historical cohort as its inclusion will lead to misinterpretation.
8. Toxicity results: The incidence of 65.3% (32 of 49) patients for G3-4 treatment-related adverse events is substantial.This reviewer would not consider such a regimen to be "welltolerated".Moreover, the incidence of 46.9% (23 of 39) patients with G3-4 adverse events during induction chemotherapy is substantial, and this reviewer is surprised that dose intensities for the chemotherapeutic agents remained at 100%? 9. Discussion: There need to be some elaboration on the mechanisms underpinning the efficacy of this regimen in targeting occult metastases in NPC.
Reviewer #2 (Remarks to the Author): with expertise in nasopharyngeal cancer, (immuno)therapy 1. Needs editing to improve English fluency.
2.Why have the investigators selected a relatively obscure IC regimen to build on?Most use either GC or TPF lite.This makes interpretation of these results a bit challenging.3. It is unclear that data were behind the modification during the study of apatinib dosing from continuous to just 5 d/ week.4. It is surprising that tumor response assessment did not include PET CT nor ct EBV DNA.
PET CT in particular is SOC many places for the evaluation 12-16 weeks post XRT and having only CT and MRI could lead to significant underdetection of persistent or recurrent disease.

5.
Were PD-L1 TPS or CPS data collected on tumors?6.It seems that the timing of biopsies on IC was not consistent.Some after one, some after two cycles, and only a fraction of the 49 patients had either biopsies.7 In the results, ctEBVDNA are reported.See item 4 above.the prespecificed plan and ct EBV DNA collection and evaluation methods should be specified.Or was this as hoc?How is " persistently" negative ct EBV DNA defined?8. Do the authors have a specific reason for having chosen camrelizumab for which reactive cutaneous capillary endothelial proliferation seems to be a challenge?9 Since the IC backbone is not standard , and there are two new agents added at the same time, what should plans be for discerning contribution of each new component of this treatment to the promising outcome?10.I would discourage any graphs showing survival data of non -randomized nonconcurrently rerated patients .This over represents the meaningfulness of the comparison.
11 It is unclear from the attached protocol how tumor volumes and LN volumes for radiation were determined.While not a primary endpoint issue, with all of these chemoradiation studies going on in NPC, it is essential for the community to understand how RT volumes , when tumor and LN volumes are changing with IC, are being addressed.Ae all plans based upon initial pre IC staging and not modified at all based upon responses to IC? Or are plans based on some modification based upon IC response?

Comments:
In the study, the investigators used NAB-TPC as induction chemotherapy regimen rather than gemcitabine and cisplatin, which is the standard of care for locoregionally advanced nasopharyngeal carcinoma.The authors should explain why.Is there any evidence supports that NAB-TPC is more efficacious than gemcitabine and cisplatin as induction chemotherapy?
In a previous phase II study evaluating camrelizumab plus apatinib in patients with recurrent or metastatic nasopharyngeal carcinoma, investigators reported that the most common (1).In the background, it's clear that there's a significant issue with distant metastasis in N3 disease patients.However, for greater emphasis and clarity, you might consider reiterating the main problem statement.This will give readers a clearer sense of the problem's importance.
(2).The predetermined values (like DMFS rates of ≤76% being considered unacceptable) are specific but might need justification.Why was this particular percentage chosen as the cutoff?This clarity can help readers understand the context better.
(3).At line 164, a minor typo exists: it should likely be "StataCorp" instead of "StateCorp."(4).At line 168, "Of them, 1 patient whose diagnosis did not meet eligibility criteria were excluded from the study".It would be more grammatically correct to state "was excluded" instead of "were excluded".
(5).The interpretation of certain statistics could be made more explicit.For example, while p-values are not mentioned in the results, as they were included in Figure 2, ensuring their interpretation is clear would be beneficial.(6).In the discussion section, the author mentioned that the DMFS rate improvement of 11.7% is presented without context.There should be a discussion on the clinical significance of this improvement.(7).As an open-label, single-arm, phase II study, the results might be prone to biases.Was the study population diverse enough to ensure the results were generalizable?
This interaction has strongly indicated that the N3 patients belong to a special group among NPC patients in their trial and there was no evidence indicating the N3 patients would benefit from GP regimen.Furthermore, in 2023 ASCO annual meeting, Dr. Jun Ma clearly reported significant heterogeneity in N stage of CONTINUUM study (As shown in the following Figure 1 of slide screenshot; Ma J, et al. 2023 ASCO abstract LBA6002, Slide #18).Specifically, the sintilimab group (sintilimab + GP induction therapy followed by CCRT and sintilimab maintenance up to total of 12 cycles) failed to significantly improve progression-free survival in advanced N stage, including N2 and N3 disease.Therefore, up to now, it is still uncertain whether the available treatment options are effective for N3 patients so far.Our group is the first to report that the TPC regimen is effective on NPC patients (Li WZ, et  To improve the prognosis of N3 patients, we optimized the TPC regimen as well as added antiangiogenic therapy and immunotherapy, designed as current QUINTUPLED regimen.And our results show that the QUINTUPLED regimen has promising distant metastasis control with acceptable safety profile in N3 NPC patients.In addition, thanks for reviewer's comment again, we have revised the statement as the following at Page 5 in the revised manuscript: Although treated with IC and CCRT, distant metastasis-free survival (DMFS) in patients with N3 disease still remains unsatisfactory, as reported by several phase III clinical trials, even with modification of IC regimen or adjuvant metronomic capecitabine.

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Comment 3. Statistical considerations: This reviewer noted the use of 1-y DMFS of 76% as a benchmark for N3 NPC for the calculation of power and sample size of this study.However, the publication referenced was dated in 2014, and this precedes all the contemporary trials of induction chemotherapy and chemoradiotherapy.Thus, one would query the legitimacy of using this benchmark -a 2-y DMFS would have been more reasonable.a.A 1-y DMFS endpoint would be influenced by several factors, including (1) the interval of imaging (note that staging investigations were only done annually); (2) whether there was onset of locoregional recurrences during the 1 year, which would have led to censoring of patients ahead of their 1 y assessment for DMFS; and (3) most importantly, the length of treatment relative to the timing of the endpoint -see Comment #5.b.On this note, this reviewer noted that staging at 1 year was done using chest radiograph and abdominal scan.Admittedly, these modalities would not be sensitive for the detection of distant metastases compared with full body CT or FDG-PET-CT.Could this have led to underreporting of events?
Response: Thanks for your expert input.At the time of design of this study in 2019, several studies focusing on N3 disease were identified and summarized in the following Table 1.There were several common points observed from these studies.Firstly, the majority of N3 patients received high-intensity treatment, including induction/adjuvant therapy and CCRT.Secondly, distant metastasis is the most important determinant of the survival rates for N3 patients despite the availability of aggressive treatment strategies of the combination of chemotherapy and radiation therapy.Thirdly, about half of distant metastasis events occurred within 1 year.Fourthly, distant metastasis control rates were similar but unsatisfactory.Although the study reference originated from our center was dated in 2014 (Sun X, et  For the onset of locoregional recurrence during 1 year, the event would be marked as locoregional failure event, is not the censoring for the endpoint of DMFS.In other words, the patient who occurred locoregional recurrence within 1 year would not be censored as a distant metastasis event, but if distant metastasis is subsequently developed, the patient would be considered as a positive event by the time of distant metastasis detected. We are sorry for the confusion of our wording in terms of re-staging.As described in our manuscript, patients underwent routine blood tests and blood biochemistry weekly during the phase of induction chemotherapy and chemoradiotherapy, and every 3 weeks during the maintenance therapy phase.Nasopharynx and neck MRI and nasopharyngeal endoscopy will be performed before and after induce chemotherapy and at the end of radiotherapy.After radiation therapy finished, routine followup evaluations (physical examination, blood examination, nasopharyngeal endoscopy, nasopharynx and neck MRI, chest CT, and abdominal CT) were routinely performed every 3 months until 3 years, every 6 months until 5 years, and annually thereafter.The restaging evaluation was done at every routine follow-up timepoint as abovementioned, not once a year!To avoid misunderstandings, we have revised the description.And for the economic factors, the chest and abdominal CT is optimal but not mandatory.Indeed, the follow up strategy of our study fully compliant with CSCO guideline, and almost eligible patients in this trial received chest and abdominal CT as their chest and abdominal examination.To date, all alive patients are being followed up and we are in constant communication with them and their families.That is the main reason that we set up primary endpoint at 1-year mark.In addition, given economic and time considerations, 1-year mark setting is logical and legitimate in this phase 2 trial.In addition, 2-and 3-year DMFS were pre-set as secondary endpoints in the present study.DMFS was calculated from the date of treatment initiation to the date of documented distant metastasis.With the median follow-up duration of 28.7 months (ranged from 22.7 to 36.7), the 98% (47/48 alive) patients were followed up for over 24 months.In our manuscript, we also reported If anything, EBV DNA and PET post-induction would have been highly informative of efficacy, especially since the concern with patients with N3 NPC is the risk of distant metastases -thus, the current measures do not offer insights in this regard.e. Perhaps, the authors could include some pre-and post-induction images of extreme responders to the induction treatment, which would be informative to the readers.

Response:
We thank the reviewer for the constructive comments.

For point 6 a:
We agree with the chance of sampling error in this study.Biopsy is not mandatory for patients who were enrolled to this trial and only 33 patients who consented to be biopsied.However, physicians who performed this kind of biopsy procedure are experienced in one of largest clinical center of NPC treatment in the world, and we have tried to minimize this kind of error.

For point 6 b:
We have added the additional key information, as the following shown, in Table 1.For point 6 c:

Lymph node levels
We did provide the EBV DNA response data in supplemental Table 7.We are showing this set of data here again to address the reviewer's concern.As we show as following, there are 48 (98%) patients who had positive plasma EBV DNA level at baseline.The EBV DNA levels became persistently undetectable in 46/48 (96%) of patients.The 41/48 (85%) and 5/48 (10%) of patients whose EBV DNA levels changed to undetectable by the end of induction therapy phase and radiotherapy phase, respectively.The remaining two patients had persistently detectable plasma EBV DNA, including one with regional PR and another suffering death due to the disease progression.
Supplemental Table S7  Comment 7. Results -Figure 2: While the data compared with the historical cohort looks promising, such an analysis is flawed.Was the historical cohort matched in some way?Otherwise, this reviewer will urge the investigators to remove the historical cohort as its inclusion will lead to misinterpretation.

Comment 3. It is unclear that data were behind the modification during the study of apatinib dosing from continuous to just 5 d/ week.
Response: Thanks for your comments.The usage of apatinib has been modified during the study.
At the beginning of the study, the schedule and dosage of apatinib was designed as day 1 to 56, 250 mg/day.In the initial stages of enrollment, we found that more than half of patients (17/25, 68%) were unable to tolerate continuous oral dosing and experienced discontinuation (detailed information of compliance to apatinib in Supplement Table S5).Due to the tolerability of the enrolled patients, we modified the initial dosage of apatinib in protocol, second version.The change was reported in the Summary of changes in protocol.As a result, after modifying the initial dosage of apatinib, more patients were able to tolerate compared to original dosing (p value = 0.032), and only 9/24 (37.5%) patients with dose interruptions.The compliance data of the apatinib was reported in Supplement Table S5.

Comment 4. It is surprising that tumor response assessment did not include PET CT nor ct EBV DNA. PET CT in particular is SOC many places for the evaluation 12-16 weeks post XRT and having only CT and MRI could lead to significant underdetection of persistent or recurrent disease.
Response: Thanks for your comments.Tumor response assessment is evaluated according to the RECIST, version 1.1.After radiation therapy finished, follow-up evaluations were performed every 3 months until 3 years, every 6 months until 5 years, and annually thereafter.Although PET/CT has ideal specificity and sensitivity for the diagnosis of distant metastases, the current high cost of PET/CT limits its wide application in the follow-up of NPC.In our study, PET CT is optimal but not mandatory.As mentioned in the CSCO guideline, currently, chest and abdomen CT and wholebody bone imaging are used commonly in the routine follow-up of NPC.Indeed, the follow up strategy of our study compliant with CSCO guideline (Zhou

Comment 5. Were PD-L1 TPS or CPS data collected on tumors?
Response: Thanks for your comments.We did not screen patients according to PD-L1 status at baseline, because the majority of patients from the endemic region had PD-L1-positive tumors and the predictive value of PD-L1 expression in nasopharyngeal carcinoma patients undergoing immunotherapy is inconclusive (Lv Comment 6.It seems that the timing of biopsies on IC was not consistent.Some after one, some after two cycles, and only a fraction of the 49 patients had either biopsies.
Response: Thanks for your comments.As the part of exploratory analysis and translational study in protocol, the purpose of lymph node puncture examination is to perform exploratory study with the goal of understanding potential mechanisms in addition to assessing pathological response.Biopsies should only be performed with the patient's consent and is not mandatory in this trial.
There is no pre-set timing of biopsies on IC.During the initial stage of the study, we found that the enlarged lymph nodes had either disappeared or shrunk to the point that they were not suitable for biopsied after three courses of IC.As a result, we performed biopsies after two cycles of IC, that we can be sure to obtain residual tumors for the exploratory analysis of the tumor characteristics and underlying mechanisms of the treatment on tumor microenvironments.In addition, the pathologic results of biopsied samples after different courses were reported in Table 2.

Comment 7. In the results, ctEBVDNA are reported. See item 4 above. the prespecificed plan and ct EBV DNA collection and evaluation methods should be specified. Or was this as hoc? How is " persistently" negative ct EBV DNA defined?
Response: Thanks for your comments.Plasma EBV DNA test were done at every routine followup timepoint (As shown in Supplemental Figure 4. Trajectories of plasma EBV DNA levels).As the part of prespecificed plan, the ctEBV DNA collection and evaluation methods were given in Supplement Appendix (in the section of Plasma Epstein-Barr virus DNA extraction and real-time quantitative polymerase chain reaction analysis)."Persistently negative ctEBV DNA" is defined as a quantitative EBV DNA level reported as 0 copies/mL and also reported as zero on subsequent tests, and we have added the statement in corresponding Supplement Appendix (in the section of Plasma Epstein-Barr virus DNA extraction and real-time quantitative polymerase chain reaction analysis).

Comment 8. Do the authors have a specific reason for having chosen camrelizumab for which reactive cutaneous capillary endothelial proliferation seems to be a challenge?
Response: We appreciate reviewer's expertise input.Camrelizumab is a humanized immunoglobulin G4/k programmed cell death- As reported in study, we acknowledge that the cumulative incidence of RCCEP in our study was higher than that reported in the CAPTAIN-1st study using combination regimen of camrelizumab plus GC to treat R/M NPC (86% versus 58%), but RCCEP was mild and controllable, and most went away spontaneously in a month after stopping the medication.And the main reasons of high incidence rate of RCCEP may result from the multiple-drug interactive effects and intensive toxicity monitoring (maintaining close communication with patients and their families) in our study on the setting of limited sample size.In addition, previous studies indicated that the occurrence of RCCEP is positively correlated with efficacy and could be a clinical biomarker for predicting efficacy of camrelizumab (Expert consensus in China 2020; Huang J, et  Therefore, the addition of the 2 new drugs would be the main contributor for the higher response rate.Indeed, based on the impressive results in the present phase 2 trial, we have designed phase 3 multicenter, randomized clinical trial (QUINTUPLED versus TPC regimen) and will start recruitment soon.

modification based upon IC response?
Response: Thanks for your comments and suggestions.All patients were treated with IMRT definitively.Target volumes were defined in accordance with the International Commission on Radiation Units and Measurements (ICRU) reports 50 and 62. Within 1-2 weeks after the third course of induction chemotherapy, all patients were immobilized in the supine position and using a thermoplastic mask that covered the head, neck, and shoulder.Both non-enhanced CT (for dose calculation) and contrast-enhanced CT (for target delineation) images were obtained from the vertex to 2 cm below the sternoclavicular joint, with 3-mm slices.And MRI fusion with simulation CT images were performed to assist the targets delineation.The primary tumor volumes were defined as the volume sum of all the known gross disease of soft tissues after IC and violated bone before treatment.The LN volumes was defined as the volume sum of all the known gross disease after IC.The high-risk clinical target volume (CTV high-risk ) was defined as the volume of a subclinical disease consisting of a 5-10 mm margin surrounding the post-IC GTVnx (2-3 mm posteriorly if adjacent to the brainstem or spinal cord) to encompass the high-risk sites of microscopic extension and the whole nasopharynx.The low-risk clinical target volume (CTV low-risk ) was defined as the high-risk clinical target volume plus a 5-10 mm margin (2-3 mm posteriorly if adjacent to the brainstem or spinal cord) to encompass the low-risk sites of microscopic extension, including the skull base, clivus, sphenoid sinus, parapharyngeal space, pterygoid fossa, retropharyngeal nodal regions, and elective neck area from level IB to level V.In order to avoid the misunderstanding, we have specifically described that element in the Supplement Appendix of revised manuscript (In the section of Description of the guidelines for intensity-modulated radiation therapy in this trial).

Responses to Reviewer #3 Comment 1. In the study, the investigators used NAB-TPC as induction chemotherapy regimen rather than gemcitabine and cisplatin, which is the standard of care for locoregionally advanced nasopharyngeal carcinoma. The authors should explain why. Is there any evidence supports that NAB-TPC is more efficacious than gemcitabine and cisplatin as induction chemotherapy?
Response: We appreciate reviewer's expert input.Indeed, our recent published phase 3 randomized clinical trial has shown that induction chemotherapy with the regimen of TPC (paclitaxel, cisplatin and capecitabine) is more efficacious than that with PF (cisplatin and CI 5-FU) for patients with stage IVA to IVB NPC (Li WZ, et

2582). How many patients in the present study have nasopharyngeal necrosis? The schedule of apatinib has been modified in second version of protocol given safety concern in the present study. The safety concern should be clarified.
Response: Thanks for your critical comments.In our study, patients received apatinib only in induction phase and stopped apatinib one week before receiving radiation with the consideration of potential nasopharyngeal necrosis.Indeed, no nasopharyngeal necrosis events have been reported among NPC patients who have not received radiotherapy.Interestingly, we did not observe the nasopharyngeal necrosis in patients treated in this trial.The usage of apatinib has been modified during the study.In the initial stages of enrollment, we found that many patients were unable to tolerate continuous oral dosing and experienced discontinuation (detailed information of compliance to apatinib in Supplement Table S5).Thereafter, we amended the protocol with modification of apatinib dose and schedule.The detailed information about the amendment was reported in the Summary of changes in protocol.The compliance data of the apatinib was also reported in Supplement Table S5.

Responses to Reviewer #4 Comment 1. In the background, it's clear that there's a significant issue with distant metastasis in N3 disease patients. However, for greater emphasis and clarity, you might consider reiterating the main problem statement. This will give readers a clearer sense of the problem's importance.
Response: Thanks for your valuable recommendation.We have revised the statement that "Here, we evaluated the efficacy and safety of the combination of camrelizumab and apatinib with IC and CCRT as a curative approach in stage TanyN3M0 NPC with the goal of significantly decreasing risk of distant metastasis." in the section of Background in revised manuscript.

Comment 2. The predetermined values (like DMFS rates of ≤ 76% being considered unacceptable) are specific but might need justification. Why was this particular percentage chosen as the cutoff? This clarity can help readers understand the context better.
Response: Thanks for your expertise input.At the time of design of this study in 2019, several studies focusing on N3 disease were identified and summarized in the following Table 1.There were several common points observed from these studies.Firstly, the majority of N3 patients received high-intensity treatment, including induction/adjuvant therapy and CCRT.Secondly, distant metastasis is the most important determinant of the survival rates for N3 patients despite the availability of aggressive treatment strategies of chemotherapy and radiation therapy.Thirdly, about half of distant metastasis events occurred within 1 year.Fourthly, distant metastasis control rates were similar but unsatisfactory.Given the quality of the literature (decided by NOS, as shown in the NOS column of Table 1) and much more detailed and reliable data derived from cohorts in our cancer center, we eventually decide the sample size based this reference.

Reviewer # 3 (
Remarks to the Author): with expertise in nasopharyngeal cancer, (immuno)therapy This manuscript describes an open-label, single-arm, phase II study evaluating the efficacy and toxicities of camrelizumab, apatinib plus induction chemotherapy and concurrent chemoradiotherapy in stage N3 nasopharyngeal carcinoma.Overall, the quality of the manuscript is good, it clearly describes the objectives, design and results of the study.

Reviewer # 4 (
complication was nasopharyngeal necrosis (9/16; 56.3%) (J Clin Oncol.2023 May 10;41(14):2571-2582). How many patients in the present study have nasopharyngeal necrosis?The schedule of apatinib has been modified in second version of protocol given safety concern in the present study.The safety concern should be clarified.Remarks to the Author): with expertise in clinical trial study design, biostatistics Thank you for submitting your manuscript.It is a well-organized manuscript and I have a few comments that you may want to consider:

Comment 4 .
Treatment procedure and compliance: When reviewing the treatment procedures, there were differences between the present trial and the prior induction chemotherapy trial of triplet versus doublet chemotherapy by the same group (Wang Zhong Li, et al.JAMA Oncol, 2022).Specifically, here, they used 3 cycles of TPX, while in the preceding trial, the investigators used 2 cycles of TPX, and here, they replaced taxol with abraxane.Additionally, they incorporated apatinib to TPX during the induction phase, and camrelizumab from induction throughout adjuvant phases of treatment; this would also imply that they have now investigated a 5-drug regimen for induction chemotherapy for high-risk NPC.a. How were these patients staged?Was it N3 by 7th or 8th edition?This was not mentioned in the main text.b.With this regimen, the authors reported a 26.5% complete response rate post-induction, but I am unsure about the tolerability of this 5-drug combo (see Comment #7 . Pathology of nasopharyngeal and lymph node tissues.Panel A and E denote hematoxylin-eosin staining of nasopharyngeal tissue and lymph node tissue before treatment.Panel B and F denote immunohistochemistry staining of cell keratins (CK, positive) in nasopharyngeal tissue and lymph node tissue before treatment, respectively.Panel C and G denote situ hybridization of Epstein-Barr encoding region (EBER, positive) in nasopharyngeal tissue and lymph node tissue before treatment, respectively.Panel D and H denote hematoxylin-eosin staining of nasopharyngeal tissue and lymph node tissue after induction therapy showing pathological complete response, respectively.
al. JAMA Oncology 2022; Liu GY, et al.JAMA Oncology 2022), and the TPC regimen has been strongly (Level I) recommended as Class IA evidence by CSCO guideline.

Supplementary Figure S6 in revised Appendix and Figure 1-2 shown in
Based on the excellent distant control rates with long-term follow up time and historical rates, the assumed sample size would be smaller under the assumption of constant type I and II errors, which strongly indicates that our sample size is adequate.Meanwhile, both 2-and 3-year DMFS were pre-set as part of secondary endpoints.With the median follow-up duration of 28.7 months (range, 22.7 to 36.7), the 98% (47/48 alive) patients were followed up for over 24 months.Furthermore, here, we reported 2-year DMFS which is sufficiently representative of long-term efficacy as indicated based on previous reports(Tang LQ, etal.Lancet Oncology 2018; Rotolo F, et al.J Natl Cancer Inst 2017).Our results show that the QUINTUPLED regimen has promising disease control in N3 NPC patients.(

Table 1 . Summary of trials for N3 NPC patients before design of the present trial. Distant metastasis predominates as the main pattern and the most lethal mode of treatment failure in patients with N3 disease (Sun XS, et al. Int J Radiat Oncol Biol Phys 2019; Li WZ, et al. JAMA Oncology 2022; Liu LT, et al. Lancet Oncology 2023). In order to directly test whether the new
regimen reduces the distant failure rate, we conducted this phase II study with the primary endpoint of DMFS.Meanwhile, the DFS was one of secondary endpoints.In fact, our results show that the QUINTUPLED regimen has promising disease control in N3 NPC patients (

). c. What was the time to starting adjuvant camrelizumab? Was there any dose reduction or treatment interruption? Did adjuvant camrelizumab delay recovery from radiotherapy toxicities? d. Perhaps more importantly, what was the scientific rationale for this quintet combination? Apatinib, which is a VEGFR2 small molecule inhibitor, has single agent activity in recurrent- metastatic NPC (Luo, et al. Oral Oncology, 2021). However, was there phase 1b data supporting the safety of this combination? This information was lacking in the Introduction and reporting of the results.
Eligible patients were aged 18-65 years with previously untreated, histologically proven non-keratinising stage T any N3M0 NPC (American Joint Committee on Cancer, 8 th edition).".Due to the nature of the single arm study, it's unclear if camrelizumab maintenance therapy delays recovery from radiotherapy toxicities, but we observed no increased in radiotherapy toxicities rates compared with historical data.In this study, in the concurrent phase, 3-4 TRAE rate of 44% is similar to the other studies (48% inCao SM, etal.Eur J Cancer 2017, and 54% in Sun Y, et al.Lancet Oncology 2016).Meanwhile, based on the results of abstract LBA6002 study in recent 2023 ASCO annual meeting, compared with chemoradiotherapy, anti-PD-1 agents combined with chemoradiotherapy obtain similar quality of life and radiotherapy discontinuation rate(0.5% vs. 0.95%, respectively) compared to standard-of-care group (Ma J, et al. 2023 ASCO abstract LBA6002).Li WF, Chen NY, et al.Induction chemotherapy plus concurrent chemoradiotherapy versus concurrent chemoradiotherapy alone in locoregionally advanced nasopharyngeal carcinoma: a phase 3, multicentre, randomised controlled trial.The Lancet Oncology 2016; 17:1509-20.3.Ma J, Sun Y, Liu X, et al.PD-1 blockade with sintilimab plus induction chemotherapy and Furthermore, apatinib synergizes antitumoral effects of camrelizumab in several solid tumors, including advanced NPC, hepatocellular carcinoma, breast cancer, and osteosarcoma (Ding X, et al.Journal of Clinical Oncology 2023, Xu J, et al.Clinical Cancer Research 2019, Li Q, et al.Clinical Cancer Research 2020, Liu J, et al.J Immunother Cancer 2020, Xie L, et al.J Immunother Cancer 2020).And recently, apatinib plus immunotherapy (and chemotherapy) demonstrated promising antitumor activity and manageable toxicity in patients with recurrent/metastatic NPC (Ding X, et al.Journal of Clinical Oncology 2023,You R, et al.Med 2022).We have revised the description in the portion of Introduction as the following "Meanwhile, antiangiogenic agent apatinib, an orally administered vascular endothelial growth factor receptor 2 (VEGFR2) tyrosine kinase inhibitor, has shown Thanks for your critical comments.As response to Reviewer #1 Comment #3 mentioned, distant metastasis is the most important determinant of the survival rates for N3 patients despite the availability of aggressive treatment strategies of chemotherapy and radiation therapy, and about half of distant metastasis events occurred within 1 year(Sun X, et al.Radiology and Oncology 2014).
Response: Thank you very much for the comments.For point 4 a: Patients' staging was defined based on the criteria of AJCC 8 th edition.We have added this statement in revised manuscript that "Reference:1.Zhang Y, Chen L, Hu GQ, et al.Gemcitabine and Cisplatin Induction Chemotherapy in Nasopharyngeal Carcinoma.The New England journal of medicine 2019; 381:1124-35.2. Sun Y, Li WF, Chen NY, et al.Induction chemotherapy plus concurrent chemoradiotherapy versus concurrent chemoradiotherapy alone in locoregionally advanced nasopharyngeal carcinoma: a phase 3, multicentre, randomised controlled trial.The Lancet Oncology 2016; 17:1509-20.3. Cao SM, Yang Q, Guo L, et al.Neoadjuvant chemotherapy followed by concurrent chemoradiotherapy versus concurrent chemoradiotherapy alone in locoregionally advanced nasopharyngeal carcinoma: A phase III multicentre randomised controlled trial.European journal of cancer (Oxford, England: 1990) 2017;75:14-23.4. Li WZ, Lv X, Hu D, et al.Effect of Induction Chemotherapy with Paclitaxel, Cisplatin, and Capecitabine vs Cisplatin and Fluorouracil on Failure-Free Survival for Patients with Stage IVA to IVB Nasopharyngeal Carcinoma: A Multicenter Phase 3 Randomized Clinical Trial.JAMA oncology 2022; 8:706-14.5. Ma J, Sun Y, Liu X, et al.PD-1 blockade with sintilimab plus induction chemotherapy and concurrent chemoradiotherapy (IC-CCRT) versus IC-CCRT in locoregionally-advanced nasopharyngeal carcinoma (LANPC): A multicenter, phase 3, randomized controlled trial (CONTINUUM).Journal of Clinical Oncology 2023;41: LBA6002-LBA.(Protocol, Second version, In 6.3.5 Camrelizumab section).And the compliance data of the camrelizumab was reported in Supplement Table S5.concurrent chemoradiotherapy (IC-CCRT) versus IC-CCRT in locoregionally-advanced nasopharyngeal carcinoma (LANPC): A multicenter, phase 3, randomized controlled trial (CONTINUUM).Journal of Clinical Oncology 2023;41: LBA6002-LBA.For point 4 d: We acknowledge that angiogenesis is a validated target in NPC, and several clinical trials have reported that antiangiogenic therapy improved the efficacy of immunotherapy.Indeed, the combination of antiangiogenic therapy with immunotherapy has been approved by the US Food and Drug Administration for the treatment of endometrial carcinoma, hepatocellular carcinoma, and renal carcinoma (Makker V, et al.N Engl J Med 2022; Finn RS, et al.N Engl J Med 2020; Motzer RJ, et al.N Engl J Med 2019; Rini BI, et al.N Engl J Med 2019).Nevertheless, monotherapy of apatinib has showed activity against NPC in several reports (Huang L, et al.Oral Oncology 2021, Li L, et al.Invest New Drugs 2020, Zhou L, et al.Drug Des Devel Ther 2020).antitumoral activity and synergetic effects with camrelizumab in several solid tumors, including advanced NPC, hepatocellular carcinoma, breast cancer, and osteosarcoma.".Response: 2-year endpoints which is sufficiently representative of long-term efficacy as indicated based on previous reports(Tang LQ, et al.Lancet Oncology 2018; Rotolo F, et al.J Natl Cancer Inst 2017).Results showed that the present QUINTUPLED regimen has promising disease control in N3 NPC patients.Results (Response to induction treatment): I have the following comments on the evaluation of response to induction treatment.a.Foremost, there seems to be a discordance between radiological response and pathological response (73.5% PR by RECIST but 84.8% pathological -ve biopsy).Could this be due to a sampling error?b.This reviewer is also intrigued by the modest CR rate of 26.5%, even with a quintet combination.With such an intensive regimen, one might have expected a higher CR rate.To interpret the data better, more information ought to be included in Table1.For example, were the nodes bulky?How many levels were involved?What was the median gross tumour volume for the primary and nodal lesions?See my Comment #4a on stage classification.c.Perhaps, it would have been very useful to have EBV DNA response data to the induction phase.What was the proportion of patients who had a complete clearance by the end of induction treatment?What was the magnitude of drop in EBV DNA counts?
(Supplementary Figure S6 in revised Appendix and Figure 1-2 of Reviewer #1 Comment #3; Li WZ, et al.JAMA Oncology 2022; Ma J, et al. 2023 ASCO abstract LBA6002; Liu LT, et al.Lancet Oncology 2023).Comment 6. d.Overall, this reviewer is unconvinced that the pathological responses are indicative of efficacy to this quintet combo.Moreover, conventional imaging, unless PET-CT, is not ideal for assessing CR of nodes; as a case in point, a lymph node of 3 cm size shrinking to 0.8 cm would be considered as PR?However, it could well be a pathological CR, since involved lymph nodes don't typically shrink entirely even months post-treatment(Li WF, et al.Oral Oncology, 2017).

Discussion: There need to be some elaboration on the mechanisms underpinning the efficacy of this regimen in targeting occult metastases in NPC. Response:
nasopharyngeal carcinoma (LANPC): A multicenter, phase 3, randomized controlled trial (CONTINUUM).Journal of Clinical Oncology 2023;41: LBA6002-LBA.We thank for this constructive comment.It is largely unknown regarding the exact mechanism on controlling distant metastasis as well as occult metastasis with our regimen.However, there are some known mechanisms which may contribute to this superior outcome.Emerging evidence has demonstrated that the antiangiogenic agents not only normalize tumor vascular network, but modulate tumor immune environment, including promoting T-cell infiltration, inducing M1 macrophage polarization, decreasing the recruitment of Treg and myeloid suppressor cell, and downregulating inhibitory immune checkpoints such as PD-L1, thereby it converts the tumor immune environment from immunesuppressive to immune-active(Zhao S, et al.Cancer Immunol Res 2019; Huang Y, et al.Proc Natl Acad Sci 2012; Du Four S, et al.Am J Cancer Res 2016; Jain RK, et al.Cancer Cell 2014).These sets of evidence suggest that combining antiangiogenic agents with immunotherapy improves efficacy by creating positive feedback loops that reinforce each other.Meanwhile, the immunostimulatory effects of radiation has also been demonstrated (Arina A, et al.Clinical cancer research 2020; Galluzzi L, et al.Nature reviews Clinical oncology 2023; Salas-Benito D, et al.Cancer Discovery 2021.).We are working on singlecell sequencing analysis derived from pre-and post-treatment biopsied samples, which may help us to identify the potential involved mechanism.
Responses to Reviewer #2 Comment 1. Needs editing to improve English fluency.
GQ, et al. 2020Nature Communications;Tang LL, et al. 2021 Cancer Communications).According to RECIST version 1.1 guideline, the same method of assessment and the same technique should be used to characterize each identified and reported lesion at baseline and during follow-up.As with previous high-quality studies, nasopharyngeal and cervical MR is the most commonly used and preferred test for examining the nasopharynx and cervical lymph nodes, taking into account the practical and financial standpoints(Zhang Y, et al.N Engl J Med 2019, Sun Y, et al.Lancet Oncology 2016).Meanwhile, plasma EBV DNA test were done at every 3-month follow-up timepoint (As shown in Zhou GQ, Wu CF, Deng B, et al.An optimal posttreatment surveillance strategy for cancer survivors based on an individualized risk-based approach.Nature communications 2020; 11:3872.2. Tang LL, Chen YP, Chen CB, et al.The Chinese Society of Clinical Oncology (CSCO) clinical guidelines for the diagnosis and treatment of nasopharyngeal carcinoma.Cancer Commun (Lond) 2021; 41:1195-227.3. Eisenhauer EA, Therasse P, Bogaerts J, et al.New response evaluation criteria in solid tumours: revised RECIST guideline (version 1.1).European journal of cancer (Oxford, Wang FH, Wei XL, Feng J, et al.Efficacy, Safety, and Correlative Biomarkers of Toripalimab in Previously Treated Recurrent or Metastatic Nasopharyngeal Carcinoma: A Phase II Clinical Trial (POLARIS-02).Journal of clinical oncology: official journal of the American Society of Clinical Oncology 2021; 39:704-12.
1 (PD-1) monoclonal antibody, and previous study reported that camrelizumab is well tolerated with antitumor activity in NPC patients before the time of design of this study in 2019 (Markham A, et al.Drugs 2019; Fang WF, et al. 2018 Lancet Oncol).

Since the IC backbone is not standard, and there are two new agents added at the same time, what should plans be for discerning contribution of each new component of this treatment to the promising outcome? Response:
al. Lancet Oncology 2020; Wang F, et al.Journal of hematology & oncology 2020).We appreciate reviewer's expertise input.Indeed, our recent published phase 3 randomized clinical trial has shown that induction chemotherapy with the regimen of TPC (paclitaxel, cisplatin and capecitabine) is more efficacious than that with PF (cisplatin and CI 5-FU) for patients with stage IVA to IVB NPC(Li WZ, et al.JAMA Oncology 2022).Currently, the TPC regimen has become Level I recommendation with Class IA evidence in the Chinese Society of Clinical Oncology (CSCO) guideline.However, none of the N3 patients who received TPC regimen reached CR status, and 2-year PFS rate with TPC regimen was only 85%.Therefore, we assume that the addition of the 2 new biological drugs likely improve the therapeutic efficacy of standard of care treatment.Meanwhile, based on our previous trial and clinical experience of paclitaxel, the incidence of its allergy was 9% (Li WZ, et al.JAMA Oncology 2022), while no allergic event occurred in NAB-paclitaxel (Ke LR, et al.Oral oncology 2017).Additionally, our recent phase 2 trial has shown encouraging anti-tumor effects and manageable toxicities in locally advanced NPC using NAB-paclitaxel (Ke LR, et al.Oral oncology 2017).In order to decrease dose-limiting toxicities of paclitaxel but improve antitumoral efficacy through increasing intratumoral concentration of paclitaxel, we replaced the paclitaxel with NAB-paclitaxel in the present trial.It is worth to mention that we are finishing a clinical trial initiated in 2019 to compare the efficacy of NAB-TPC versus GP in advanced NPC and the upcoming public data shows that NAB-TPC regimen as a first-line treatment provided superior PFS versus GP regimen for advanced NPC (Median IRC-assessed PFS, 11.3 m versus 7.7 m, p=0.002; chictr.org.cnregistrationnumber:ChiCTR1900027112).It is impressive that the QUINTUPLED regimen obtained a high CR rate of 26% after induction phase.We agree with that it is hard to tease out the real factors that contribute to this higher response rate given the nature of the trial design.However, in our previously reported phase 3 clinical trial(Li WZ, et al.JAMA Oncology 2022), we observed a much lower but similar CR rate to IC between TPC and PF regimen (1.7% and 3.3%, respectively), which indicates that the higher CR rate would derive from the addition of the two new drugs rather than the switch from CI 5FU to capecitabine.Meanwhile, in terms of the switch from CI 5FU to capecitabine, similar tumor response rates were observed between 5-FU and capecitabine groups in both anal cancer and advanced metastatic gastric cancer(Jones CM, etal, Int J Radiat Oncol Biol Phys 2018; Chen, J et al, Asia Pac J Clin Oncol 2018), as well as in rectal cancer (O'Connell MJ, et al, J Clin Oncol 2014).

Comment 2. In a previous phase II study evaluating camrelizumab plus apatinib in patients with recurrent or metastatic nasopharyngeal carcinoma, investigators reported that the most common complication was nasopharyngeal necrosis (9/16; 56.3%) (J Clin Oncol. 2023 May 10;41(14):2571-
al. JAMA Oncology 2022).Currently, the TPC regimen has become a Level I recommendation with Class IA evidence in the Chinese Society of Clinical Oncology (CSCO) guideline.Meanwhile, based on our previous trial and clinical experience of paclitaxel, the incidence of its allergy was 9%, while no allergic event occurred in NAB-paclitaxel.Nevertheless, our recent phase 2 trial has shown NAB-paclitaxel has encouraging antitumoral effects and manageable toxicities in patients with locally advanced NPC(Ke LR, et al.Oral  oncology 2017).In order to decrease dose-limiting toxicities of paclitaxel but improve anti-tumor efficacy via increasing intratumoral concentration of paclitaxel, we replace the paclitaxel with NABpaclitaxel in the present trial.It is worth to mention that we are finishing a clinical trial initiated in 2019 to compare the efficacy of NAB-TPC versus GP in advanced NPC.The upcoming public data shows that NAB-TPC regimen as a first-line treatment provided superior PFS versus GP regimen for advanced NPC (Median IRC-assessed PFS, 11.3 m versus 7.7 m, p=0.002; chictr.org.cnregistrationnumber:ChiCTR1900027112).LiWZ, Lv X, Hu D, et al.Effect of Induction Chemotherapy with Paclitaxel, Cisplatin, and Capecitabine vs Cisplatin and Fluorouracil on Failure-Free Survival for Patients with Stage IVA to IVB Nasopharyngeal Carcinoma: A Multicenter Phase 3 Randomized Clinical Trial.JAMA oncology 2022; 8:706-14.2. Ke LR, Xia WX, Qiu WZ, et al.A phase II trial of induction NAB-paclitaxel and cisplatin followed by concurrent chemoradiotherapy in patients with locally advanced nasopharyngeal carcinoma.Oral oncology 2017; 70:7-13.

Table 1 . Summary of trials for N3 NPC patients before design of the present trial.
Reference:1.Wong FC, Ng AW, Lee VH, et al.Whole-field simultaneous integrated-boost intensitymodulated radiotherapy for patients with nasopharyngeal carcinoma.International journal of radiation oncology, biology, physics 2010;76:138-45.